/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.accumulo.server.security.handler;

import java.util.Set;

import org.apache.accumulo.core.client.AccumuloSecurityException;
import org.apache.accumulo.core.client.security.tokens.AuthenticationToken;
import org.apache.accumulo.server.ServerContext;

/**
 * This interface is used for the system which will be used for authenticating a user. If the
 * implementation does not support configuration through Accumulo, it should throw an
 * AccumuloSecurityException with the error code UNSUPPORTED_OPERATION
 */
public interface Authenticator {

  void initialize(ServerContext context);

  boolean validSecurityHandlers();

  void initializeSecurity(String principal, byte[] token);

  boolean authenticateUser(String principal, AuthenticationToken token)
      throws AccumuloSecurityException;

  Set<String> listUsers();

  /**
   * Creates a user with no initial permissions whatsoever
   */
  void createUser(String principal, AuthenticationToken token) throws AccumuloSecurityException;

  void dropUser(String user) throws AccumuloSecurityException;

  void changePassword(String principal, AuthenticationToken token) throws AccumuloSecurityException;

  /**
   * Checks if a user exists
   */
  boolean userExists(String user);

  Set<Class<? extends AuthenticationToken>> getSupportedTokenTypes();

  /**
   * Returns true if the given token is appropriate for this Authenticator
   */
  boolean validTokenClass(String tokenClass);
}
